According to Business Insider, videos posted to YouTube, appear to show the American, complete with Jihadist beard and kuffeyeh scarf, joining the Jabhat al-Nusra fighters.

“Bashar Assad, your days are numbered,” the man says in one of the videos, “You are going down in flames. You should just quit now, while you can, and leave. You are going to die, no matter what. Where you go we will find you and kill you. Do you understand?”

Despite the Nusra group recently being designated as a terrorist organization by his home country, the Yanki-Jihadi appears thrilled to be fighting alongside other members.

In the first of the videos, posted on the sharing site by 'Abu Adam Hourani', the American is described as a 'mujahid', meaning a person fighting a religious war.

And while the U.S. government has condemned the use of violence in Syria, this U.S. national seems to revel in it. In a further clip, he is shown celebrating after his team shoot down a Syrian regime helicopter.

Bizarrely, this is the not the only American to be rumored to be fighting alongside the Syrian opposition. When the YouTube footage first appeared, Syrian netizens speculated that the Yanki-Jihadi could be the infamous Matthew VanDyke, a man who first fought alongside the Libyan rebels before joining the Syrian opposition fighters.

However, he has denied the rumors and wrote on his Twitter account that the man in the new footage was just a "war tourist" rather than a fully blown member of Jabhat al-Nusra.

Should foreign national be taking matters into their own hands like this? Is it time for the U.S. government to intervene in Syria? Tell us what you think below.